Products derived from isoindole of general formula: ##STR3## having an opiate activity had been described in U.S. Pat. No. 4,042,707. These products do not have any activity towards substance P.
To date, despite the research carried out and despite the interest raised [M. R. Hanley, TINS, (5) 139 (1982)], no product acting specifically on substance P and having a non-peptide structure had been discovered and it is for this reason that the isoindolone derivatives of formula (I) are of considerable value.